Handicap Equations - NIOSH 1997
nUses 1000, 2000, 3000, and 4000 Hz. 
  
nThe equation was first proposed for detecting the early effects of noise on inner ear function.
   
nIt is now used by the Federal Government for compensation purposes.
nDobie, fells that this is not the best equation to use, since the mean frequency of speech recognition is 1600 Hz.  The best representative frequencies are 500, 1000, 2000, & 4000 Hz
(Dobie RA, 1998)